Commutator-brush



(No Model.)

H. G. REIST. GOMMUTATOR BRUSH.

No. 501,960. Patented July 25, 1893.

NITED STATES PATENT Orrlcs.

HENRY G. REIST, OF LYNN, ASSIGNOR TO THE GENERAL ELECTRIC COMPANY, OF BOSTON, MASSACHUSETTS.

COMMUTATt'JFl-BRUSH.

SFECIFICATION forming part of Letters Patent No. 501,960, dated July 25, 1893.

Application filed March 15, 1893.

To all whom it may concern:

Be it known that I, HENRY G. REIsT, a citizen of the United States, residing at Lynn, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements in Commutator-Brushes, of which the following is a specification.

My invention relates to commutator or current collecting brushes for dynamo electric to machines and has for its object to provide a brush of great carrying capacity and relatively high specific resistance, whereby a large current may be carried to translating devices of any kind while the sparking due [5 to short-circuiting segments of the commutator is reduced to a minimum. The construction I adopt to attain these ends is more fully described hereinafter.

In order to attain a high specific resist- 2o ance, carbon brushes have been used, and have been found desirable; but the current carrying capacity of such brushes is extremely small, and it has not been found advisable to use them with currents of low potential, less than one hundred volts or thereabout. They are not therefore adapted to dynamos giving large current of low poten tial or to motors, as they require a large commutator and a multiplicity of brushes in such 0 case. It is to avoid the faults in such brushes that I have devised my present invention.

In the drawing hereto annexed and hereby made a part of this specification I show in perspective a representation of a brush embodying my invention.

A represents such a brush composed as shown of several laminee of German silver or other conducting material, B B. These laminae are fastened together at their back ends by rivets or solder, thus making good electric connection with one another. At the top and bottom I put backing plates, as D D, for the purpose of giving increased stiffness to the brush.

As thus constructed the brush would be similar to those in common use and open to all their objections; but in order to increase the specific resistance of the brushes 1 cut transverse slits E E in the laminae B extend- Serial No. 466,086. (No model.)

ing a greater or less distance across each one of them, and by this means I attain the objects desired. The brush thus constructed may be secured to any suitable brush holder and may he slid forward or back between the plates D D, to adjust its position with referonce to the commutator C, in the usual manner. The slits E E are to be punched so as to adjust the resistance of the brush to the potential of the current it is to carry, or to the difference of potential between the commntator segments.

In some cases I prefer to arrange the slits in the laminae B B at other than a right angle to their length, as in the wear of the brush this does not make a sudden change in its current-carryin g capacity when it reaches the slit; the slit is thus presented diagonally to the commutator, and the brush wears gradually away from one side to the other. This construction is shown by dotted lines in the 7 drawing.

It is manifest further that electrical connection between the laminte may be made by their contact merely; and they may therefore be loosely assembled and then brought into closer contact by a clamp or by the brush holder, if so desired.

It is preferable to have an insulating film between the sheets or metal lamime such as a coating of insulating scale, varnish, or thin paper interposed, or the like, extending between the sheets or laminae except Where they are fastened together or united at the outer part of the brush.

Having thus described my invention, what I claim, and wish to protect by Letters Patent of the United States, is-

1. A commutator brush composed of laminze having transverse slits, substantially as described. 0

2. A commutator brush composed of superposed laminze as B B having transverse slits as E E, the laminze inclosed between backing plates as D D, substantially as described.

3. A commutator brush composed of laminze B B connected together at their rear ends and inclosed between backing plates as I) D, the laminae having transverse slits as E E,

whereby the specific resistance of the brush strips Whose continuity is interrupted by is increased. transverse slits, substantially as described. l0

4. A commutator brush composed of lami- In Witness whereof I have hereunto set my nze as B B having transverse slits as E E, and hand this 13th day of March, 1893. 5 inclosed and movable hack and forth between HENRY G. REIST.

backing plates as D D. Vitnesses:

5. As articles of manufacture, laminae for ELIHU THOMSON, commutator brushes composed of metallic JOHN "W. GIBBONEY. 

